//! Anthropic cassette regression coverage for empty `end_turn` tool follow-ups.
//!
//! Run cassette tests in replay mode by default, or set
//! `RIG_PROVIDER_TEST_MODE=record` to record against the real provider.

use std::sync::{
    Arc,
    atomic::{AtomicUsize, Ordering},
};

use rig::{
    client::CompletionClient,
    completion::{CompletionModel, Prompt, ToolDefinition},
    message::{AssistantContent, Message, UserContent},
    providers::anthropic::completion::CLAUDE_SONNET_4_6,
    tool::Tool,
};
use serde::Deserialize;
use serde_json::json;

const TERMINAL_NOTIFY_PREAMBLE: &str = "\
When the user reports their status, call `notify` with a short summary. \
Do not answer with any normal assistant text before or after the tool call. \
Once the tool result is available, the assistant turn is complete and you must end the turn with no content.";

const TERMINAL_NOTIFY_WITH_ACK_PREAMBLE: &str = "\
When the user reports their status, first write one short sentence acknowledging that you are sending the notification. \
Then call `notify` with a short summary. \
After the tool result is available, stop immediately and do not send any more assistant text.";

const TERMINAL_NOTIFY_PROMPT: &str = "I finished the deploy.";

#[derive(Deserialize)]
struct NotifyArgs {
    msg: String,
}

#[derive(Debug, thiserror::Error)]
#[error("notify error")]
struct NotifyError;

fn notify_tool_definition() -> ToolDefinition {
    ToolDefinition {
        name: Notify::NAME.to_string(),
        description: "Send a short notification for a user status update.".to_string(),
        parameters: json!({
            "type": "object",
            "properties": {
                "msg": {
                    "type": "string",
                    "description": "The short notification to send."
                }
            },
            "required": ["msg"]
        }),
    }
}

struct Notify {
    call_count: Arc<AtomicUsize>,
}

impl Notify {
    fn new(call_count: Arc<AtomicUsize>) -> Self {
        Self { call_count }
    }
}

impl Tool for Notify {
    const NAME: &'static str = "notify";
    type Error = NotifyError;
    type Args = NotifyArgs;
    type Output = String;

    async fn definition(&self, _prompt: String) -> ToolDefinition {
        notify_tool_definition()
    }

    async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
        self.call_count.fetch_add(1, Ordering::SeqCst);
        Ok(format!("sent: {}", args.msg))
    }
}

fn assistant_message_has_notify_tool_call(message: &Message) -> bool {
    matches!(
        message,
        Message::Assistant { content, .. }
            if content.iter().any(|item| matches!(
                item,
                AssistantContent::ToolCall(tool_call) if tool_call.function.name == Notify::NAME
            ))
    )
}

fn assistant_message_has_nonempty_text_and_notify_tool_call(message: &Message) -> bool {
    matches!(
        message,
        Message::Assistant { content, .. }
            if content.iter().any(|item| matches!(
                item,
                AssistantContent::Text(text) if !text.text.trim().is_empty()
            )) && content.iter().any(|item| matches!(
                item,
                AssistantContent::ToolCall(tool_call) if tool_call.function.name == Notify::NAME
            ))
    )
}

fn message_has_tool_result(message: &Message) -> bool {
    matches!(
        message,
        Message::User { content }
            if content.iter().any(|item| matches!(item, UserContent::ToolResult(_)))
    )
}

fn history_has_empty_assistant_text(messages: &[Message]) -> bool {
    messages.iter().any(|message| {
        matches!(
            message,
            Message::Assistant { content, .. }
                if content.iter().any(|item| matches!(
                    item,
                    AssistantContent::Text(text) if text.text.is_empty()
                ))
        )
    })
}

#[tokio::test]
async fn raw_followup_empty_end_turn_normalizes_to_empty_text_choice() {
    super::super::support::with_anthropic_cassette(
        "empty_end_turn/raw_followup_empty_end_turn_normalizes_to_empty_text_choice",
        |client| async move {
            let model = client.completion_model(CLAUDE_SONNET_4_6);

            let first_turn = model
                .completion_request(TERMINAL_NOTIFY_PROMPT)
                .preamble(TERMINAL_NOTIFY_PREAMBLE.to_string())
                .max_tokens(1024)
                .tool(notify_tool_definition())
                .send()
                .await
                .expect("first Anthropic turn should succeed");

            let tool_call = first_turn
                .choice
                .iter()
                .find_map(|item| match item {
                    AssistantContent::ToolCall(tool_call) => Some(tool_call.clone()),
                    _ => None,
                })
                .expect("first Anthropic turn should emit a notify tool call");

            let followup = model
                .completion_request(Message::tool_result_with_call_id(
                    tool_call.id.clone(),
                    tool_call.call_id.clone(),
                    "sent: deploy finished",
                ))
                .preamble(TERMINAL_NOTIFY_PREAMBLE.to_string())
                .max_tokens(1024)
                .message(Message::Assistant {
                    id: first_turn.message_id.clone(),
                    content: first_turn.choice.clone(),
                })
                .send()
                .await
                .expect("follow-up Anthropic turn should not error on empty end_turn");

            assert_eq!(
                followup.choice.len(),
                1,
                "expected normalized empty follow-up choice, got {:?}",
                followup.choice
            );

            match followup.choice.first() {
                AssistantContent::Text(text) => assert!(
                    text.text.is_empty(),
                    "expected empty follow-up text sentinel, got {:?}",
                    text.text
                ),
                other => panic!("expected empty text sentinel, got {other:?}"),
            }
        },
    )
    .await;
}

#[tokio::test]
async fn prompt_loop_accepts_empty_terminal_turn_after_tool_result() {
    let call_count = Arc::new(AtomicUsize::new(0));
    super::super::support::with_anthropic_cassette(
        "empty_end_turn/prompt_loop_accepts_empty_terminal_turn_after_tool_result",
        |client| async move {
            let agent = client
                .agent(CLAUDE_SONNET_4_6)
                .preamble(TERMINAL_NOTIFY_PREAMBLE)
                .max_tokens(1024)
                .tool(Notify::new(call_count.clone()))
                .build();

            let response = agent
                .prompt(TERMINAL_NOTIFY_PROMPT)
                .max_turns(5)
                .extended_details()
                .await
                .expect("agent prompt should not fail on an empty terminal Anthropic turn");

            assert!(
                response.output.trim().is_empty(),
                "expected empty final output for the terminal tool prompt, got {:?}",
                response.output
            );
            assert!(
                call_count.load(Ordering::SeqCst) >= 1,
                "notify should be called at least once"
            );

            let messages = response
                .messages
                .expect("extended details should include history");
            assert!(
                messages.iter().any(assistant_message_has_notify_tool_call),
                "expected notify tool call in history, got {:?}",
                messages
            );
            assert!(
                messages.iter().any(message_has_tool_result),
                "expected tool result in history, got {:?}",
                messages
            );
            assert!(
                !history_has_empty_assistant_text(&messages),
                "history should not contain the normalized empty assistant sentinel: {:?}",
                messages
            );
        },
    )
    .await;
}

#[tokio::test]
async fn prompt_loop_preserves_pre_tool_text_when_terminal_followup_is_empty() {
    let call_count = Arc::new(AtomicUsize::new(0));
    super::super::support::with_anthropic_cassette("empty_end_turn/prompt_loop_preserves_pre_tool_text_when_terminal_followup_is_empty", |client| async move {
    let agent = client
        .agent(CLAUDE_SONNET_4_6)
        .preamble(TERMINAL_NOTIFY_WITH_ACK_PREAMBLE)
        .max_tokens(1024)
        .tool(Notify::new(call_count.clone()))
        .build();

    let response = agent
        .prompt(TERMINAL_NOTIFY_PROMPT)
        .max_turns(5)
        .extended_details()
        .await
        .expect("agent prompt should preserve prior-turn text when Anthropic ends empty");

    assert!(
        response.output.trim().is_empty(),
        "expected empty final output for the terminal tool prompt, got {:?}",
        response.output
    );
    assert!(
        call_count.load(Ordering::SeqCst) >= 1,
        "notify should be called at least once"
    );

    let messages = response
        .messages
        .expect("extended details should include history");
    assert!(
        messages
            .iter()
            .any(assistant_message_has_nonempty_text_and_notify_tool_call),
        "expected an assistant message that preserved pre-tool text alongside the notify tool call, got {:?}",
        messages
    );
    assert!(
        messages.iter().any(message_has_tool_result),
        "expected tool result in history, got {:?}",
        messages
    );
    assert!(
        !history_has_empty_assistant_text(&messages),
        "history should not contain the normalized empty assistant sentinel: {:?}",
        messages
    );

    })
    .await;
}
